KR102783687B1 - Semiconductor light emitting devices and display devices - Google Patents

Abstract

A semiconductor light emitting device includes a light emitting portion, a first electrode on a lower portion and a side portion of the light emitting portion, a second electrode on an upper portion of the light emitting portion, a plurality of trenches on the side portion of the light emitting portion, and a passivation layer on the side portion of the light emitting portion, wherein an end of the passivation layer can be positioned in one of the plurality of trenches.

Description

Semiconductor light emitting devices and display devices

The invention relates to semiconductor light-emitting devices and display devices.

Display devices use self-luminous elements such as light-emitting diodes (LEDs) as light sources for pixels to display high-quality images. Light-emitting diodes exhibit excellent durability even under harsh environmental conditions and are capable of long life and high brightness, and are thus attracting attention as light sources for next-generation display devices.

Recently, research is being conducted to manufacture ultra-small light-emitting diodes using highly reliable inorganic crystal structure materials and to place them on the panel of a display device (hereinafter referred to as “display panel”) to use them as next-generation light sources.

These display devices are expanding beyond flat panel displays into various forms such as flexible displays, foldable displays, stretchable displays, and rollable displays.

In order to implement high resolution, pixel sizes are gradually becoming smaller, and light-emitting elements must be aligned in numerous pixels of such smaller sizes. Therefore, research is actively being conducted on the manufacture of ultra-small light-emitting diodes that are micro- or nano-scale in size.

Typically, display devices include tens of millions or more pixels. Therefore, it is very difficult to align at least one light-emitting element to each of the tens of millions or more small pixels, so various studies on methods for aligning light-emitting elements in display panels are actively being conducted recently.

As the size of light-emitting elements decreases, the ability to quickly and accurately transfer these light-emitting elements onto a substrate has become a very important issue to be resolved. Transfer technologies that have been recently developed include the pick and place process, the laser lift-off method, and the self-assembly method. In particular, the self-assembly method, which transfers light-emitting elements onto a substrate using a magnetic material (or magnet), has recently been in the spotlight.

In the self-assembly method, a large number of light-emitting elements are dropped into a fluid-containing tank, and the light-emitting elements dropped into the fluid are moved to pixels on a substrate as a result of the movement of a magnetic body, so that the light-emitting elements are aligned to each pixel. Therefore, the self-assembly method is gaining attention as a next-generation transfer method because it can quickly and accurately transfer a large number of light-emitting elements onto a substrate.

Meanwhile, the light-emitting element assembled on the substrate by the self-assembly method is electrically connected by the thermal compression method. That is, the bonding layer provided on the lower part of the light-emitting element is melted by the thermal compression and electrically connected to the electrical wiring of the substrate.

However, the following problems arise when thermally compressing a bonding layer of a conventional light-emitting element.

Figure 1 illustrates how the bonding material escapes around the light-emitting element.

As illustrated in Fig. 1, when the light-emitting element (4) is thermally compressed after being assembled into the assembly hole (3), the bonding material (5) on the lower side of the light-emitting element (4) escapes around the light-emitting element (4) rather than remaining between the light-emitting element (4) and the substrate (1). In this way, the bonding material (5) escapes around the light-emitting element (4), and some of the bonding material (5) forms a sharp spire as high as the height of the light-emitting element (4). When the electrode wiring (not illustrated) is arranged on the upper side of the light-emitting element (4) through a post-process, the electrode wiring electrically contacts the bonding material (5), causing a problem in which the upper and lower parts of the light-emitting element (5) are electrically short-circuited.

Figure 2 is a cross-sectional view illustrating a conventional light-emitting element.

As shown in Fig. 2, a bonding material (5) is provided on the lower side of a conventional light-emitting element. In the past, a structure was not provided to prevent the bonding material (5) from escaping laterally during thermal compression.

Accordingly, when the conventional light-emitting element illustrated in FIG. 2 is thermally bonded onto a substrate (1) using a thermal compression method as illustrated in FIG. 1, the bonding material (5) melted by the heat generated during the thermal compression process does not remain at the lower side of the light-emitting element (4) but escapes to the periphery of the light-emitting element (4).

Figure 3 illustrates the appearance of a light-emitting element being detached.

In the case where the bonding material (5) previously escaped around the light-emitting element (4), since there is almost no bonding material (5) between the light-emitting element (4) and the substrate (1), the light-emitting element (4) is not attached to the substrate (1) but is detached, as illustrated in FIG. 3. That is, the light-emitting element (5) is attached to the substrate (1) by the bonding material (5). In order for the light-emitting element (5) to be strongly attached to the substrate (1), a certain amount of bonding material (5) must exist on the lower side of the light-emitting element (5) despite thermal compression. However, during thermal compression, most of the bonding material (5) provided on the lower side of the light-emitting element (5) escapes around the light-emitting element (5), and only a small amount of bonding material (5) remains on the lower side of the light-emitting element (5). Therefore, the light-emitting element (5) is not strongly attached to the substrate (1), so there is a problem in that the light-emitting element (5) is easily detached from the substrate (1). Detachment of the light emitting element (5) reduces the assembly rate and causes assembly failure or lighting failure.

Figure 4 illustrates a faulty electrical connection between the electrical wiring of the light-emitting element and the substrate.

As illustrated in Fig. 4, when the bonding material (5) is removed around the light-emitting element (4) by thermal compression, there is almost no bonding material (5) remaining on the lower side of the light-emitting element (4) (see region X), and thus, a poor electrical connection occurs between the light-emitting element (4) and the substrate (1) via the bonding material (5). That is, since the bonding material (5) does not exist continuously between the light-emitting element (4) and the substrate (1) but exists locally, the electrical connection between the light-emitting element (4) and the substrate (1) is also locally connected. This leads to an increase in the electrical resistance between the light-emitting element (4) and the substrate (1), and thus, there is a problem that the luminance is reduced because the electrical signal of the substrate (1) is not easily supplied to the light-emitting element (4).

The present invention aims to solve the above-mentioned and other problems.

Another object of the present invention is to provide a semiconductor light-emitting device in which the formation position of a passivation layer can be freely controlled.

Another object of the present invention is to provide a semiconductor light-emitting device in which a first electrode can be easily formed on a side of a light-emitting portion.

Another object of the invention is to provide a display device capable of achieving high brightness by having a semiconductor light-emitting element with improved light extraction efficiency.

Another object of the invention is to provide a display device capable of preventing bonding failure.

Another object of the present invention is to provide a display device capable of enhancing bonding strength.

Another object of the present invention is to provide a display device capable of preventing assembly defects and lighting defects.

The technical problems of the embodiment are not limited to those described in this article, but include those that can be understood through the description of the invention.

According to one aspect of the embodiment to achieve the above or other purposes, a semiconductor light emitting device includes: a light emitting portion; a first electrode on a lower portion and a side of the light emitting portion; a second electrode on an upper portion of the light emitting portion; a plurality of trenches on the side of the light emitting portion; and a passivation layer on the side of the light emitting portion, wherein an end of the passivation layer can be positioned in one of the plurality of trenches.

The plurality of trenches may be arranged along the perimeter of the side of the light emitting portion.

The end of the first electrode can be positioned in the one trench.

An end of the first electrode can be in contact with an end of the passivation layer in the one trench.

The tip of the first electrode may be positioned on the passivation layer.

Each of the above plurality of trenches may have an asymmetrical groove.

According to another aspect of the embodiment, a display device includes: a substrate; first and second assembly wirings on the substrate; a partition wall disposed on the first and second assembly wirings and having an assembly hole; a semiconductor light-emitting element in the assembly hole; and a connecting electrode disposed in the assembly hole and connecting the semiconductor light-emitting element to at least one of the first and second assembly wirings, wherein the semiconductor light-emitting element includes: a light-emitting portion; a first electrode on a lower portion and a side portion of the light-emitting portion; a second electrode on an upper portion of the light-emitting portion; a plurality of trenches on the side portion of the light-emitting portion; and a passivation layer on the side portion of the light-emitting portion, wherein an end of the passivation layer is positioned in one of the plurality of trenches.

The above connecting electrode can be arranged along the periphery of the semiconductor light-emitting element within the above assembly hole.

The display device includes an insulating layer on the partition wall; and electrode wiring connected to the semiconductor light-emitting element through the insulating layer.

As illustrated in FIG. 11, the embodiment is such that a trench (1110, 1120 1130) that determines the formation position of a passivation layer (157) is arranged on the side of a semiconductor light-emitting element (150), and a first electrode (154) having a constant height is arranged on the side of the semiconductor light-emitting element (150), thereby preventing unevenness in image quality between sub-pixels on a substrate (310) in a display device (300), thereby improving image quality.

The embodiment can connect the semiconductor light emitting element (150) to at least one of the first assembly wiring (321) and the second assembly wiring (322) by using the connecting electrode (350). That is, the first electrode (154) is arranged along the side periphery of the light emitting portion (151, 152, 153) of the semiconductor light emitting element (150), and the connecting electrode (350) can be in contact with the first electrode (154). Accordingly, by connecting the connecting electrode (350) to the first electrode (154) along the side periphery of the light emitting portion (151, 152, 153) of the semiconductor light emitting element (150), the contact area between the connecting electrode (350) and the semiconductor light emitting element (150) is maximized, so that maximum brightness can be obtained.

In addition, since the connection electrodes (350) are arranged in the assembly holes (345) of each of the plurality of sub-pixels defined on the substrate (310) with a uniform size, the contact area between the connection electrodes (350) and the semiconductor light-emitting element (150) is the same, so that uniform brightness is obtained between the plurality of sub-pixels, and the image quality can be improved.

In addition, since the semiconductor light emitting element (150) of each pixel is stably electrically connected to the connection electrode (350), lighting failure can be prevented.

In addition, a connecting electrode (350) is placed between the outer side of the semiconductor light-emitting element (150) and the inner side of the assembly hole (345) within the assembly hole (345), so that the semiconductor light-emitting element (150) is firmly attached to the substrate (310) and/or the partition wall (340) by the connecting electrode (350), thereby preventing detachment of the semiconductor light-emitting element (150).

In addition, since the connecting electrode (350) is formed only within the assembly hole (345), an electrical short between the connecting electrode (350) and the electrode wiring (372) formed by the post-process can be prevented.

Meanwhile, as illustrated in FIG. 13, since light generated in the active layer (152) is reflected or scattered by a plurality of trenches so that more light is extracted, the light extraction efficiency is improved, so that the brightness can be improved.

In addition, as illustrated in FIG. 12, a plurality of trenches (1110, 1120, 1130) are arranged on the side of the semiconductor light-emitting element (150), and a first electrode (154) and a passivation layer (157) are arranged in the trenches (1110, 1120, 1130), so that the contact area between each of the first electrode (154) and the passivation layer (157) and the side of the semiconductor light-emitting element (150) increases, thereby preventing the first electrode (154) and the passivation layer (157) from being detached.

In addition, as illustrated in FIG. 11, the connection electrode (350) is in contact with the outer surface of the semiconductor light-emitting element (150), at least one of the first and second assembly wires (321, 322), and the inner surface of the assembly hole (345), thereby enhancing the fixation of the semiconductor light-emitting element (150), thereby enhancing reliability.

Further scope of applicability of the embodiments will become apparent from the detailed description below. However, since various changes and modifications within the spirit and scope of the embodiments will become apparent to those skilled in the art, it should be understood that the detailed description and specific embodiments, such as the preferred embodiments, are given by way of example only.

Figure 1 illustrates how the bonding material escapes around the light-emitting element.
Figure 2 is a cross-sectional view illustrating a conventional light-emitting element.
Figure 3 illustrates the appearance of a light-emitting element being detached.
Figure 4 illustrates a faulty electrical connection between the electrical wiring of the light-emitting element and the substrate.
FIG. 5 illustrates a living room of a house in which a display device according to an embodiment is placed.
FIG. 6 is a block diagram schematically showing a display device according to an embodiment.
Fig. 7 is a circuit diagram showing an example of a pixel of Fig. 6.
Figure 8 is an enlarged view of the first panel area in the display device of Figure 5.
Figure 9 is an enlarged view of area A2 of Figure 8.
FIG. 10 is a drawing showing an example in which a light-emitting element according to an embodiment is assembled on a substrate by a self-assembly method.
Fig. 11 is a cross-sectional view illustrating a display device according to an embodiment.
Fig. 12 is a cross-sectional view illustrating a semiconductor light-emitting device according to the first embodiment.
Figure 13 illustrates the path of light propagation in a semiconductor light-emitting device according to the first embodiment.
Figure 14 shows the lighting distribution of a display device equipped with light-emitting elements electrically connected through a conventional bonding method.
Figure 15 shows the lighting distribution of a display device having semiconductor light-emitting elements electrically connected through a deposition method in an embodiment.
Figures 16 to 29 illustrate a manufacturing process of a semiconductor light-emitting device according to the first embodiment.
Fig. 30 is a cross-sectional view illustrating a semiconductor light-emitting device according to the second embodiment.
The size, shape, and dimensions of components depicted in the drawings may differ from the actual ones. In addition, even if the same components are depicted with different sizes, shapes, and dimensions between drawings, this is only an example in the drawings, and the same components may have the same sizes, shapes, and dimensions between drawings.

Hereinafter, embodiments disclosed in the present specification will be described in detail with reference to the attached drawings. Regardless of the drawing symbols, identical or similar components will be given the same reference numerals and redundant descriptions thereof will be omitted. The suffixes 'module' and 'part' used for components in the following description are assigned or used interchangeably in consideration of the ease of writing the specification, and do not in themselves have distinct meanings or roles. In addition, the attached drawings are intended to facilitate easy understanding of the embodiments disclosed in the present specification, and the technical ideas disclosed in the present specification are not limited by the attached drawings. In addition, when an element such as a layer, region, or substrate is mentioned as existing 'on' another element, this includes that it may be directly on the other element or that other intermediate elements may exist therebetween.

The display devices described in this specification may include TVs, signage, mobile phones, smart phones, HUDs (head-up displays) for automobiles, backlight units for laptop computers, displays for VR or AR, etc. However, the configuration according to the embodiments described in this specification may also be applied to devices capable of displaying, even if they are new product types developed in the future.

A light-emitting element and a display device including the same according to the following embodiments are described.

FIG. 5 illustrates a living room of a house in which a display device according to an embodiment is placed.

Referring to FIG. 5, the display device (100) of the embodiment can display the status of various electronic products such as a washing machine (101), a robot vacuum cleaner (102), and an air purifier (103), communicate with each electronic product based on IoT, and control each electronic product based on user setting data.

A display device (100) according to an embodiment may include a flexible display manufactured on a thin and flexible substrate. The flexible display can be bent or rolled like paper while maintaining the characteristics of a conventional flat panel display.

In a flexible display, visual information can be implemented by independently controlling the emission of unit pixels arranged in a matrix form. A unit pixel means a minimum unit for implementing one color. The unit pixel of a flexible display can be implemented by a light-emitting element. In an embodiment, the light-emitting element may be a Micro-LED or a Nano-LED, but is not limited thereto.

FIG. 6 is a block diagram schematically showing a display device according to an embodiment, and FIG. 7 is a circuit diagram showing an example of a pixel of FIG. 6.

Referring to FIGS. 6 and 7, a display device according to an embodiment may include a display panel (10), a driving circuit (20), a scan driving unit (30), and a power supply circuit (50).

The display device (100) of the embodiment can drive light-emitting elements in an active matrix (AM) manner or a passive matrix (PM) manner.

The driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

The display panel (10) may be formed in a rectangular shape, but is not limited thereto. That is, the display panel (10) may be formed in a circular or oval shape. At least one side of the display panel (10) may be formed to be bent at a predetermined curvature.

The display panel (10) can be divided into a display area (DA) and a non-display area (NDA) arranged around the display area (DA). The display area (DA) is an area where pixels (PX) are formed to display an image. The display panel (10) can include data lines (D1 to Dm, m is an integer greater than or equal to 2), scan lines (S1 to Sn, n is an integer greater than or equal to 2) intersecting the data lines (D1 to Dm), a high-potential voltage line (VDDL) to which a high-potential voltage is supplied, a low-potential voltage line (VSSL) to which a low-potential voltage is supplied, and pixels (PX) connected to the data lines (D1 to Dm) and the scan lines (S1 to Sn).

Each of the pixels (PX) may include a first sub-pixel (PX1), a second sub-pixel (PX2), and a third sub-pixel (PX3). The first sub-pixel (PX1) may emit a first color light of a first main wavelength, the second sub-pixel (PX2) may emit a second color light of a second main wavelength, and the third sub-pixel (PX3) may emit a third color light of a third main wavelength. The first color light may be red light, the second color light may be green light, and the third color light may be blue light, but is not limited thereto. In addition, although FIG. 6 illustrates that each of the pixels (PX) includes three sub-pixels, the present invention is not limited thereto. That is, each of the pixels (PX) may include four or more sub-pixels.

Each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) may be connected to at least one of the data lines (D1 to Dm), at least one of the scan lines (S1 to Sn), and a high-potential voltage line (VDDL). The first sub-pixel (PX1) may include light-emitting elements (LD), a plurality of transistors for supplying current to the light-emitting elements (LD), and at least one capacitor (Cst), as shown in FIG. 7.

Although not shown in the drawing, each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) may include only one light-emitting element (LD) and at least one capacitor (Cst).

Each of the light emitting elements (LDs) may be a semiconductor light emitting diode including a first electrode, a plurality of conductive semiconductor layers, and a second electrode. Here, the first electrode may be an anode electrode, and the second electrode may be a cathode electrode, but is not limited thereto.

The light emitting device (LD) can be one of a horizontal light emitting device, a flip chip light emitting device, and a vertical light emitting device.

The plurality of transistors may include a driving transistor (DT) for supplying current to the light-emitting elements (LD), and a scan transistor (ST) for supplying a data voltage to a gate electrode of the driving transistor (DT), as shown in FIG. 7. The driving transistor (DT) may include a gate electrode connected to a source electrode of the scan transistor (ST), a source electrode connected to a high-potential voltage line (VDDL) to which a high-potential voltage is applied, and a drain electrode connected to first electrodes of the light-emitting elements (LD). The scan transistor (ST) may include a gate electrode connected to a scan line (Sk, where k is an integer satisfying 1 ≤ k ≤ n), a source electrode connected to the gate electrode of the driving transistor (DT), and a drain electrode connected to a data line (Dj, where j is an integer satisfying 1 ≤ j ≤ m).

A capacitor (Cst) is formed between the gate electrode and the source electrode of the driving transistor (DT). The storage capacitor (Cst) charges the difference between the gate voltage and the source voltage of the driving transistor (DT).

The driving transistor (DT) and the scan transistor (ST) may be formed as thin film transistors. In addition, although FIG. 7 has described the driving transistor (DT) and the scan transistor (ST) as being formed as P-type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), the present invention is not limited thereto. The driving transistor (DT) and the scan transistor (ST) may also be formed as N-type MOSFETs. In this case, the positions of the source electrodes and the drain electrodes of each of the driving transistor (DT) and the scan transistor (ST) may be changed.

In addition, although FIG. 7 illustrates that each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) includes a 2T1C (2 Transistor - 1 capacitor) having one driving transistor (DT), one scan transistor (ST), and one capacitor (Cst), the present invention is not limited thereto. Each of the first sub-pixel (PX1), the second sub-pixel (PX2), and the third sub-pixel (PX3) may include a plurality of scan transistors (ST) and a plurality of capacitors (Cst).

Since the second sub-pixel (PX2) and the third sub-pixel (PX3) can be expressed in substantially the same circuit diagram as the first sub-pixel (PX1), a detailed description thereof is omitted.

The driving circuit (20) outputs signals and voltages for driving the display panel (10). For this purpose, the driving circuit (20) may include a data driving unit (21) and a timing control unit (22).

The data driving unit (21) receives digital video data (DATA) and a source control signal (DCS) from the timing control unit (22). The data driving unit (21) converts digital video data (DATA) into analog data voltages according to the source control signal (DCS) and supplies them to the data lines (D1 to Dm) of the display panel (10).

The timing control unit (22) receives digital video data (DATA) and timing signals from the host system. The timing signals may include a vertical sync signal, a horizontal sync signal, a data enable signal, and a dot clock. The host system may be an application processor of a smartphone or tablet PC, a monitor, a system on chip of a TV, etc.

The timing control unit (22) generates control signals for controlling the operation timing of the data driving unit (21) and the scan driving unit (30). The control signals may include a source control signal (DCS) for controlling the operation timing of the data driving unit (21) and a scan control signal (SCS) for controlling the operation timing of the scan driving unit (30).

The driving circuit (20) may be placed in a non-display area (NDA) provided on one side of the display panel (10). The driving circuit (20) may be formed as an integrated circuit (IC) and mounted on the display panel (10) using a COG (chip on glass) method, a COP (chip on plastic) method, or an ultrasonic bonding method, but the present invention is not limited thereto. For example, the driving circuit (20) may be mounted on a circuit board (not shown) rather than on the display panel (10).

The data driving unit (21) may be mounted on the display panel (10) using a COG (chip on glass) method, a COP (chip on plastic) method, or an ultrasonic bonding method, and the timing control unit (22) may be mounted on a circuit board.

The scan driving unit (30) receives a scan control signal (SCS) from the timing control unit (22). The scan driving unit (30) generates scan signals according to the scan control signal (SCS) and supplies them to the scan lines (S1 to Sn) of the display panel (10). The scan driving unit (30) may include a plurality of transistors and may be formed in a non-display area (NDA) of the display panel (10). Alternatively, the scan driving unit (30) may be formed as an integrated circuit, in which case it may be mounted on a gate flexible film attached to the other side of the display panel (10).

The circuit board may be attached to pads provided at one edge of the display panel (10) using an anisotropic conductive film. As a result, lead lines of the circuit board may be electrically connected to the pads. The circuit board may be a flexible film such as a flexible printed circuit board, a printed circuit board, or a chip on film. The circuit board may be bent to the bottom of the display panel (10). As a result, one side of the circuit board may be attached to one edge of the display panel (10), and the other side may be connected to a system board disposed at the bottom of the display panel (10) and equipped with a host system.

The power supply circuit (50) can generate voltages required for driving the display panel (10) from the main power applied from the system board and supply them to the display panel (10). For example, the power supply circuit (50) can generate a high-potential voltage (VDD) and a low-potential voltage (VSS) for driving light-emitting elements (LD) of the display panel (10) from the main power and supply them to a high-potential voltage line (VDDL) and a low-potential voltage line (VSSL) of the display panel (10). In addition, the power supply circuit (50) can generate and supply driving voltages for driving the driving circuit (20) and the scan driving unit (30) from the main power.

Figure 8 is an enlarged view of the first panel area in the display device of Figure 3.

Referring to FIG. 8, the display device (100) of the embodiment can be manufactured by mechanically and electrically connecting a plurality of panel areas, such as the first panel area (A1), through tiling.

The first panel area (A1) may include a plurality of light-emitting elements (150) arranged for each unit pixel (PX of FIG. 6).

For example, a unit pixel (PX) may include a first sub-pixel (PX1), a second sub-pixel (PX2), and a third sub-pixel (PX3). For example, a plurality of red light-emitting elements (150R) may be arranged in the first sub-pixel (PX1), a plurality of green light-emitting elements (150G) may be arranged in the second sub-pixel (PX2), and a plurality of blue light-emitting elements (150B) may be arranged in the third sub-pixel (PX3). The unit pixel (PX) may further include a fourth sub-pixel in which no light-emitting elements are arranged, but is not limited thereto.

Figure 9 is an enlarged view of area A2 of Figure 8.

Referring to FIG. 9, the display device (100) of the embodiment may include a substrate (200), assembly wiring (201, 202), an insulating layer (206), and a plurality of light-emitting elements (150). More components may be included.

The assembly wiring may include a first assembly wiring (201) and a second assembly wiring (202) that are spaced apart from each other. The first assembly wiring (201) and the second assembly wiring (202) may be provided to generate a dielectric force for assembling the light emitting element (150). For example, the light emitting element (150) may be one of a horizontal light emitting element, a flip chip light emitting element, and a vertical light emitting element.

The light-emitting element (150) may include a red light-emitting element (150), a green light-emitting element (150G), and a blue light-emitting element (150B0) to form a unit pixel (sub-pixel), but is not limited thereto, and may also implement red and green, respectively, by providing a red fluorescent substance and a green fluorescent substance.

The substrate (200) may be a support member that supports components placed on the substrate (200) or a protective member that protects the components.

The substrate (200) may be a rigid substrate or a flexible substrate. The substrate (200) may be formed of sapphire, glass, silicon, or polyimide. In addition, the substrate (200) may include a flexible material such as PEN (Polyethylene Naphthalate) or PET (Polyethylene Terephthalate). In addition, the substrate (200) may be a transparent material, but is not limited thereto.

The substrate (200) may be a backplane equipped with circuits, such as transistors (ST, DT), capacitors (Cst), signal wiring, etc., within the sub-pixels (PX1, PX2, PX3) illustrated in FIGS. 4 and 5, but is not limited thereto.

The insulating layer (206) may include an insulating and flexible organic material such as polyimide, PAC, PEN, PET, polymer, etc., or an inorganic material such as silicon oxide (SiO2) or silicon nitride series (SiNx), and may be formed integrally with the substrate (200) to form a single substrate.

The insulating layer (206) may be a conductive adhesive layer having adhesiveness and conductivity, and the conductive adhesive layer may have flexibility to enable a flexible function of the display device. For example, the insulating layer (206) may be a conductive adhesive layer such as an anisotropic conductive film (ACF) or an anisotropic conductive medium, a solution containing conductive particles, etc. The conductive adhesive layer may be a layer that is electrically conductive in a direction vertical to the thickness, but electrically insulating in a direction horizontal to the thickness.

The insulating layer (206) may include an assembly hole (203) into which a light-emitting element (150) is inserted. Therefore, during self-assembly, the light-emitting element (150) may be easily inserted into the assembly hole (203) of the insulating layer (206). The assembly hole (203) may be called an insertion hole, a fixing hole, an alignment hole, or the like.

The assembly hole (203) may be different depending on the shape of the light-emitting element (150). For example, the red light-emitting element, the green light-emitting element, and the blue light-emitting element each have different shapes and may have an assembly hole (203) having a shape corresponding to the shape of each of these light-emitting elements. For example, the assembly hole (203) may include a first assembly hole for assembling the red light-emitting element, a second assembly hole for assembling the green light-emitting element, and a third assembly hole for assembling the blue light-emitting element. For example, the red light-emitting element may have a circular shape, the green light-emitting element may have a first oval shape having a first short axis and a second long axis, and the blue light-emitting element may have a second oval shape having a second short axis and a second long axis, but this is not limited thereto. The second long axis of the oval shape of the blue light-emitting element may be larger than the second long axis of the oval shape of the green light-emitting element, and the second short axis of the oval shape of the blue light-emitting element may be smaller than the first short axis of the oval shape of the green light-emitting element.

FIG. 10 is a drawing showing an example in which a light-emitting element according to an embodiment is assembled on a substrate by a self-assembly method.

The self-assembly method of a light-emitting element is described with reference to FIGS. 9 and 10.

The substrate (200) may be a panel substrate of a display device. In the following description, the substrate (200) is described as a panel substrate of a display device, but the embodiment is not limited thereto.

The substrate (200) may be formed of glass or polyimide. In addition, the substrate (200) may include a flexible material such as PEN (Polyethylene Naphthalate) or PET (Polyethylene Terephthalate). In addition, the substrate (200) may be a transparent material, but is not limited thereto.

Referring to FIG. 10, a light emitting element (150) may be placed in a chamber (1300) filled with a fluid (1200). The fluid (1200) may be water such as ultrapure water, but is not limited thereto. The chamber may be called a tank, a container, a vessel, or the like.

After this, the substrate (200) can be placed on the chamber (1300). Depending on the embodiment, the substrate (200) can also be introduced into the chamber (1300).

As illustrated in FIG. 9, a pair of assembly wirings (201, 202) corresponding to each light-emitting element (150) to be assembled may be arranged on the substrate (200).

The assembly wiring (201, 202) may be formed of a transparent electrode (ITO) or may include a metal material having excellent electrical conductivity. For example, the assembly wiring (201, 202) may be formed of at least one of titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), and molybdenum (Mo), or an alloy thereof.

An electric field is formed between the assembly wiring (201, 202) by an externally supplied voltage, and a dielectric force can be formed between the assembly wiring (201, 202) by this electric field. The light-emitting element (150) can be fixed to the assembly hole (203) on the substrate (200) by this dielectric force.

The gap between the assembly wires (201, 202) is formed smaller than the width of the light-emitting element (150) and the width of the assembly hole (203), so that the assembly position of the light-emitting element (150) can be fixed more precisely using an electric field.

An insulating layer (206) is formed on the assembly wiring (201, 202) to protect the assembly wiring (201, 202) from the fluid (1200) and prevent leakage of current flowing in the assembly wiring (201, 202). The insulating layer (206) may be formed as a single layer or multiple layers of an inorganic insulator such as silica or alumina or an organic insulator.

Additionally, the insulating layer (206) may include an insulating and flexible material such as polyimide, PEN, PET, etc., and may be formed integrally with the substrate (200) to form a single substrate.

The insulating layer (206) may be an adhesive insulating layer or a conductive adhesive layer having conductivity. The insulating layer (206) may be flexible to enable a flexible function of the display device.

The insulating layer (206) has a partition wall, and an assembly hole (203) can be formed by this partition wall. For example, when forming the substrate (200), a part of the insulating layer (206) is removed, so that each of the light-emitting elements (150) can be assembled into the assembly hole (203) of the insulating layer (206).

An assembly hole (203) is formed in the substrate (200) into which light-emitting elements (150) are combined, and the surface on which the assembly hole (203) is formed can come into contact with a fluid (1200). The assembly hole (203) can guide the exact assembly position of the light-emitting elements (150).

Meanwhile, the assembly hole (203) may have a shape and size corresponding to the shape of the light-emitting element (150) to be assembled at the corresponding position. Accordingly, it is possible to prevent another light-emitting element from being assembled in the assembly hole (203) or a plurality of light-emitting elements from being assembled.

Referring again to FIG. 10, after the substrate (200) is placed, an assembly device (1100) including a magnetic body can move along the substrate (200). For example, a magnet or an electromagnet can be used as the magnetic body. The assembly device (1100) can move in contact with the substrate (200) to maximize the area affected by the magnetic field into the fluid (1200). Depending on the embodiment, the assembly device (1100) may include a plurality of magnetic bodies or may include magnetic bodies having a size corresponding to that of the substrate (200). In this case, the movement distance of the assembly device (1100) may be limited to a predetermined range.

By the magnetic field generated by the assembly device (1100), the light emitting element (150) within the chamber (1300) can move toward the assembly device (1100).

The light emitting element (150) may move toward the assembly device (1100) and enter the assembly hole (203) to come into contact with the substrate (200).

At this time, the light emitting element (150) in contact with the substrate (200) can be prevented from being detached by the movement of the assembly device (1100) due to the electric field applied by the assembly wiring (201, 202) formed on the substrate (200).

That is, since the time required for each light-emitting element (150) to be assembled on the substrate (200) can be drastically shortened by the self-assembly method using the electromagnetic field described above, a large-area, high-pixel display can be implemented more quickly and economically.

A predetermined solder layer (not shown) may be further formed between the light-emitting element (150) assembled on the assembly hole (203) of the substrate (200) and the substrate (200) to improve the bonding strength of the light-emitting element (150).

Afterwards, electrode wiring (not shown) can be connected to the light-emitting element (150) to supply power.

Next, although not shown, at least one insulating layer may be formed by a post-process. The at least one insulating layer may be a transparent resin or a resin containing a reflective material or a scattering material.

Meanwhile, the embodiment arranges a trench capable of determining a formation position of a passivation layer on a side of a semiconductor light-emitting element, so that an end of the passivation layer is positioned in the trench, so that a first electrode having a constant height can be arranged on the side of the semiconductor light-emitting element. Accordingly, the connection electrode is arranged in a uniform area on the first electrode of the semiconductor light-emitting element arranged in the assembly hole of each of the plurality of sub-pixels, so that uniform brightness can be secured between each of the plurality of sub-pixels, thereby improving the image quality. In addition, the embodiment may have various technical advantages, and these various technical advantages will be described in detail below.

Any explanation omitted below can be readily understood from FIGS. 5 to 10 and the description given above in connection with the corresponding drawings.

Fig. 11 is a cross-sectional view illustrating a display device according to an embodiment.

Referring to FIG. 11, a display device (300) according to an embodiment may include a substrate (310), a first assembly wiring (321), a second assembly wiring (322), a partition wall (340), a semiconductor light-emitting element (150), and a connecting electrode (350). The display device (300) according to the first embodiment may include more components than this.

Since the substrate (310) and the partition wall (340) are each identical to the substrate (200) and the insulating layer (206) illustrated in FIG. 9, a detailed description is omitted.

The partition wall (340) may be arranged on the substrate (310). For example, the partition wall (340) may be arranged on the first assembly wiring (321) and the second assembly wiring (322). The partition wall (340) may be referred to as an insulating layer. The partition wall (340) may have a plurality of assembly holes (345). The assembly holes (345) may be provided in sub-pixels of a pixel, but are not limited thereto. The assembly holes (345) guide and fix the assembly of the semiconductor light-emitting element (150), and the semiconductor light-emitting element (150) moved by a magnetic body during self-assembly may be moved from near the assembly hole (345) into the assembly hole (345) and fixed to the assembly hole (345).

Although the drawing shows the assembly hole (345) as having an inclined inner side, it may also have an inner side that is perpendicular to the upper surface of the substrate (310). The semiconductor foot and component can be easily inserted into the assembly hole (345) by the assembly hole (345) having an inclined inner side.

The first assembly wiring (321) and the second assembly wiring (322) may be arranged on the substrate (310). The first assembly wiring (321) and the second assembly wiring (322) may be provided to generate a dielectric force for assembling the light emitting element (150).

Since the first and second assembly wirings (321, 322) are each identical to the electrode wirings (201, 202) illustrated in Fig. 9, a detailed description is omitted.

Meanwhile, the first insulating layer (330) may be disposed on the substrate (310). The first and second assembly wirings (321, 322) may be disposed between the first insulating layer (330) and the substrate (310). The first assembly wiring (321) and the second assembly wiring (322) may be disposed on the same layer, for example, the substrate (310). That is, the first assembly wiring (321) and the second assembly wiring (322) may be in contact with the upper surface of the substrate (310). The first assembly wiring (321) and the second assembly wiring (322) may be spaced apart from each other to prevent an electrical short. An AC voltage may be applied to the first assembly wiring (321) and the second assembly wiring (322), so that a dielectric force may be formed between the first assembly wiring (321) and the second assembly wiring (322). The semiconductor light emitting element (150) positioned in the assembly hole (345) can be fixed by this dielectric force. Since the first assembly wiring (321) and the second assembly wiring (322) are horizontally arranged in parallel on the same layer, the dielectric force formed between the first assembly wiring (321) and the second assembly wiring (322) is uniform, so the semiconductor light emitting element (150) can be positioned at the center of the assembly hole (345).

The first insulation layer (330) can protect the first assembly wiring (321) and the second assembly wiring (322) from the fluid (1200 of FIG. 9) and prevent leakage current flowing through the first assembly wiring (321) and the second assembly wiring (322).

The first insulating layer (330) can increase the dielectric force. For example, the first insulating layer (330) can be a dielectric layer. The first insulating layer (330) can be formed of a material having a high dielectric constant. The dielectric force can be proportional to the dielectric constant of the first insulating layer (330). Therefore, the dielectric force formed between the first assembly wiring (321) and the second assembly wiring (322) is increased by the first insulating layer (330) made of a material having a high dielectric constant, and the semiconductor light emitting element (150) positioned within the assembly hole (345) can be more firmly fixed by the increased dielectric force.

For example, the first insulating layer (330) may be formed of a single layer or multiple layers of inorganic materials such as silica or alumina or organic materials.

For example, the first insulating layer (330) may include an insulating and flexible material such as polyimide, PEN, PET, etc. For example, the first insulating layer (330) may be formed integrally with the substrate (310) to form a single substrate. That is, the first assembly wiring (321) and the second assembly wiring (322) may be embedded in the substrate (310).

The first insulating layer (330) may be an adhesive insulating layer or a conductive adhesive layer having conductivity. When the first insulating layer (330) is a conductive adhesive layer, the first assembly wiring (321) and the second assembly wiring (322) may be surrounded by the insulating layer to prevent an electrical short between each of the first assembly wiring (321) and the second assembly wiring (322) and the conductive adhesive layer. For example, the first insulating layer (330) may be flexible to enable a flexible function of the display device (300).

A semiconductor light emitting element (150) can be placed in each of a plurality of assembly holes (345) provided on a substrate (310).

The semiconductor light-emitting element (150) can be formed of a semiconductor material, such as a group IV compound or a group III-V compound. The semiconductor light-emitting element (150) is a member that generates light according to an electrical signal.

As an example, the semiconductor light-emitting element (150) arranged in each assembly hole (345) can generate a single color light. For example, the semiconductor light-emitting element (150) can generate ultraviolet light, purple light, blue light, etc. In this case, the semiconductor light-emitting element (150) arranged in each assembly hole (345) serves as a light source, and can generate various color light using this light source to display an image. A color conversion layer and a color filter can be provided to generate various color light.

As another example, the semiconductor light-emitting element (150) arranged in each assembly hole (345) may be one of a blue semiconductor light-emitting element, a green semiconductor light-emitting element, and a red semiconductor light-emitting element. For example, when three assembly holes (345) are arranged in a parallel manner, the semiconductor light-emitting element (150) arranged in the first assembly hole (345) may be a blue semiconductor light-emitting element, the semiconductor light-emitting element (150) arranged in the second assembly hole (345) may be a green semiconductor light-emitting element, and the semiconductor light-emitting element (150) arranged in the third assembly hole (345) may be a red semiconductor light-emitting element.

The connecting electrode (350) may be placed in the assembly hole (345). The connecting electrode (350) may be called a connecting portion, a connecting member, a connecting metal, etc.

The connecting electrode (350) can connect the semiconductor light emitting element (150) to at least one of the first and second assembly wirings (321, 322). The connecting electrode (350) can be made of a metal having excellent electrical conductivity. The connecting electrode (350) can be made of at least one layer. For example, the connecting electrode (350) can be made of three layers of molybdenum/aluminum/molybdenum (Mo/Al/Mo), but is not limited thereto.

For example, the connecting electrode (350) may be arranged along the perimeter of the side of the semiconductor light-emitting element (150) within the assembly hole (345). For example, the connecting electrode (350) may be electrically connected to the side of the semiconductor light-emitting element along the perimeter of the side of the semiconductor light-emitting element (150) within the assembly hole (345).

As shown in FIGS. 1 to 4, when thermally pressing using a bonding method, a bonding material (5) provided on the lower part of a light-emitting element (4) is attached to a substrate (1) by pressure.

However, the bonding material (5) on the lower side of the light-emitting element (4) escapes to the periphery of the light-emitting element (4) rather than staying between the light-emitting element (4) and the substrate (1), and an electrical short occurs with the electrode wiring formed by the post-process due to the bonding material (5) that escapes to the periphery (Fig. 1). In addition, the light-emitting element (4) is not firmly attached to the substrate (1), and thus the light-emitting element (4) is detached (Fig. 3). In addition, the bonding material (5) on the lower side of the light-emitting element (4) escapes to the periphery of the light-emitting element (4) rather than staying, and thus the amount of bonding material (5) remaining between the light-emitting element (4) and the substrate (1) is small, and thus the electrical contact area between the light-emitting element (4) and the electrode wiring of the substrate (1) is small, and thus a decrease in brightness is caused due to an increase in contact resistance (Fig. 4).

The first embodiment is intended to solve these problems and may have the following technical advantages.

According to the first embodiment, a connecting electrode (350) is placed between the outer side of the semiconductor light-emitting element (150) and the inner side of the assembly hole (345) within the assembly hole (345), so that the semiconductor light-emitting element (150) is firmly attached to the substrate (310) and/or the partition wall (340) by the connecting electrode (350), thereby preventing detachment of the semiconductor light-emitting element (150).

According to the first embodiment, since the connecting electrode (350) is formed only within the assembly hole (345), an electrical short between the connecting electrode (350) and the electrode wiring (372) formed by the post-process can be prevented.

According to the first embodiment, since the connecting electrode (350) is electrically connected to the side of the semiconductor light-emitting element (150) along the periphery of the side of the semiconductor light-emitting element (150), the contact area between the connecting electrode (350) and the semiconductor light-emitting element (150) is maximized, so that maximum brightness can be obtained.

According to the first embodiment, since the connection electrodes (350) are arranged in the assembly holes (345) of each of the plurality of sub-pixels defined on the substrate (310) with a uniform size, the contact area between the connection electrodes (350) and the semiconductor light-emitting element (150) is the same, so that uniform brightness is secured between the plurality of sub-pixels, thereby improving the image quality.

According to the first embodiment, since the semiconductor light-emitting element (150) of each pixel is stably electrically connected to the connection electrode (350), lighting failure can be prevented.

As shown in Fig. 14, when a light-emitting element (4) is attached to a substrate (1) by thermal compression using a bonding method of the prior art (Fig. 1, Fig. 3 and Fig. 4), it can be seen that the light-emitting element (4) of each of a plurality of sub-pixels is turned on or not turned on, resulting in a reduced lighting rate.

As illustrated in FIG. 15, when a semiconductor light-emitting element (150) is attached to a substrate (310) by a deposition method according to the first embodiment, it can be seen that the semiconductor light-emitting elements (150) of a plurality of sub-pixels are turned on, thereby significantly improving the lighting rate.

Meanwhile, a semiconductor light emitting device (150) may be placed in an assembly hole (345). A semiconductor light emitting device (150) according to an embodiment may have a plurality of trenches (1110, 1120, 1130) placed on its side. One of the plurality of trenches, for example, the first trench (1110), may determine a formation position of a passivation layer (157). That is, an end of the passivation layer (157) may be located in the first trench (1110).

[Example 1]

Fig. 12 is a cross-sectional view illustrating a semiconductor light-emitting device according to the first embodiment.

Referring to FIG. 12, a semiconductor light-emitting device (150) according to the first embodiment may include a light-emitting portion (151, 152, 153), a first electrode (154), a second electrode (155), trenches (1110, 1120, 1130), and a passivation layer (157). The semiconductor light-emitting device (150) according to the first embodiment may include more components than this. The passivation layer (157) may be called an insulating layer, a protective layer, or the like.

The light emitting portion may include a first conductive semiconductor layer (151), an active layer (152), and a second conductive semiconductor layer (153). That is, the active layer (152) may be disposed on the first conductive semiconductor layer (151), and the second conductive semiconductor layer (153) may be disposed on the active layer (152).

The first conductive semiconductor layer (151), the active layer (152), and the second conductive semiconductor layer (153) can be sequentially grown on a wafer (401 in FIG. 16) using deposition equipment such as MOCVD. Thereafter, the second conductive semiconductor layer (153), the active layer (152), and the first conductive semiconductor layer (151) can be etched in the vertical direction in this order using an etching process. Thereafter, a passivation layer (157) is formed along the remaining area except for a part of the side surface of the first conductive semiconductor layer (151), that is, along another part of the side surface of the first conductive semiconductor layer (151), the side surface of the active layer (152), and the side surface perimeter of the second conductive semiconductor layer (153), thereby manufacturing a semiconductor light-emitting device (150).

The first conductive semiconductor layer (151) may include a first conductive dopant, and the second conductive semiconductor layer (153) may include a second conductive dopant. For example, the first conductive dopant may be an n-type dopant such as silicon (Si), and the second conductive dopant may be a p-type dopant such as boron (B).

For example, the first conductive semiconductor layer (151) may be a place where electrons are generated, and the second conductive semiconductor layer (153) may be a place where holes are formed. The active layer (152) may be called a light-emitting layer as it is a place where light is generated.

The first electrode (154) may be placed on the lower portion of the light-emitting portion (151, 152, 153). The first electrode (154) may be placed on the side of the light-emitting portion (151, 152, 153). The second electrode (155) may be placed on the upper portion of the light-emitting portion (151, 152, 153). The first electrode (154) and the second electrode (155) supply current to the light-emitting portion (151, 152, 153), so that light having a brightness corresponding to the current may be emitted from the light-emitting portion (151, 152, 153).

The first electrode (154) and the second electrode (155) may be made of a metal having excellent electrical conductivity. The first electrode (154) and the second electrode (155) may be made of at least one layer. The first electrode (154) and the second electrode (155) may be made of different metals, but are not limited thereto.

For example, at least one of the first electrode (154) and the second electrode (155) may include a magnetic layer. For example, as illustrated in FIG. 10, when magnetized by a magnetic body of an assembly device (1100), a semiconductor light-emitting element (150) including a magnetic layer may be moved toward the magnetic body of the assembly device (1100) by an attractive force applied to the magnetic body. Accordingly, the semiconductor light-emitting element (150) may be moved along the moving direction of the magnetic body of the assembly device (1100). In this way, the semiconductor light-emitting element (150) that is moving may be pulled by a dielectrophoretic force formed in the assembly hole (345) on the substrate (310) and assembled into the assembly hole (345).

Meanwhile, the first electrode (154) may include a reflective layer. In this case, light generated in the active layer (152) is reflected, thereby improving light extraction efficiency and enhancing brightness.

The passivation layer (157) may be disposed on the side of the light-emitting portion (151, 152, 153). The passivation layer (157) may be disposed on the upper portion of the light-emitting portion (151, 152, 153). For example, the passivation layer (157) may be disposed on the second electrode (155) of the light-emitting portion (151, 152, 153).

For example, the passivation layer (157) can protect the light emitting portion (151, 152, 153).

For example, the passivation layer (157) can block leakage current of the light-emitting portion (151, 152, 153). Leakage current can flow through the side surfaces of the light-emitting portion (151, 152, 153), that is, the side surface of the first conductive semiconductor layer (151), the side surface of the active layer (152), and the side surface of the second conductive semiconductor layer (153). By forming the passivation layer (157) on the side surface of the first conductive semiconductor layer (151), the side surface of the active layer (152), and the side surface of the second conductive semiconductor layer (153), leakage current can be prevented.

For example, the passivation layer (157) can assist in the assembly of the semiconductor light-emitting device (150). That is, by controlling the arrangement area of the first electrode (154) and the passivation layer (157) arranged on the outer surface of the semiconductor light-emitting device (150), the semiconductor light-emitting device (150) can be pulled into the assembly hole (345) by the dielectrophoretic force formed between the first assembly wiring (321) and the second assembly wiring (322). For example, when the first electrode (154) of the semiconductor light-emitting device (150) is arranged close to the first assembly wiring (321) and the second assembly wiring (322), and the passivation layer (157) is arranged far from the first assembly wiring (321) and the second assembly wiring (322), the semiconductor light-emitting device (150) can be pulled into the assembly hole (345) by the dielectrophoretic force. Accordingly, the semiconductor light emitting element (150) can be continuously fixed in the assembly hole (345) after being pulled into the assembly hole (345) by the dielectrophoretic force. Thereafter, even if the dielectrophoretic force is not generated, the semiconductor light emitting element (150) can be fixed in the assembly hole (345) by natural forces such as surface tension or van der Waals force.

For example, an opening (158) in which a passivation layer (157) is not formed may be formed in a part of the second electrode (155) of the light-emitting portion (151, 152, 153). As will be described later, the electrode wiring (372) may be electrically connected to the second electrode (155) of the semiconductor light-emitting element (150) through the opening (158).

Meanwhile, the passivation layer (157) may be formed on a part of the side of the light-emitting portion (151, 152, 153). That is, the passivation layer (157) may be disposed on one area of the side of the light-emitting portion (151, 152, 153), and the first electrode (154) may be disposed on another area of the side of the light-emitting portion (151, 152, 153).

The first electrode (154) is formed on the side of the light-emitting portion (151, 152, 153) to facilitate electrical connection to the connecting electrode (350). The larger the area of the first electrode (154) formed on the side of the light-emitting portion (151, 152, 153), the larger the contact area between the connecting electrode (350) and the first electrode (154). In this case, current flows more smoothly to the light-emitting portion (151, 152, 153) and a greater amount of light is output, which means that the brightness is improved.

Since the first electrode (154) is formed after the passivation layer (157) is formed, the passivation layer (157) must be formed limited to one area of the side of the light-emitting portion (151, 152, 153), so that it is easy to form the first electrode (154) limited to another area of the side of the light-emitting portion (151, 152, 153). However, it is very difficult to form the passivation layer (157) limited to one area of the light-emitting portion (151, 152, 153) in terms of the manufacturing process. Accordingly, it is very difficult to form the first electrode (154) limited to another area of the side of the light-emitting portion (151, 152, 153).

In the embodiment, a plurality of trenches are formed in the light-emitting portion (151, 152, 153), and the passivation layer (157) can be easily formed limited to one area of the light-emitting portion (151, 152, 153) by using the plurality of trenches, and accordingly, the first electrode (154) can also be easily formed limited to another area of the light-emitting portion (151, 152, 153).

Accordingly, the plurality of trenches can serve as stoppers to ensure that the passivation layer (157) is formed only in one area of the side of the light-emitting portion (151, 152, 153).

For example, the passivation layer (157) may be positioned at the end (157a) of the first trench (1110) among the plurality of trenches formed in the light-emitting portions (151, 152, 153), for example, the first trench (1110). That is, the passivation layer (157) may be formed on the upper and side portions of the light-emitting portions (151, 152, 153), but may be positioned in the first trench (1110) provided on the side portion of the light-emitting portions (151, 152, 153). Accordingly, the passivation layer (157) may not be formed on the side portion of the light-emitting portions (151, 152, 153) located below the first trench (1110). A first electrode (154) can be formed on the side of the light emitting portion (151, 152, 153) located under the first trench (1110).

Accordingly, the first trench (1110) may be a boundary region between the passivation layer (157) and the first electrode (154). That is, the end (157a) of the passivation layer and the end (154a) of the first electrode (154) may come into contact in the first trench (1110).

For example, a plurality of trenches may be arranged along the perimeter of the side of the light-emitting portion (151, 152, 153), but this is not limited thereto. Accordingly, an end (157a) of the passivation layer (157) and an end (154a) of the first electrode (154) may be in contact in the first trench (1110) arranged along the perimeter of the side of the light-emitting portion (151, 152, 153). That is, with respect to the first trench (1110), the passivation layer (157) may be arranged along the perimeter of the side of the light-emitting portion (151, 152, 153) positioned above the first trench (1110), and the first electrode (154) may be arranged along the perimeter of the side of the light-emitting portion (151, 152, 153) positioned below the first trench (1110).

Each of the plurality of trenches may have an asymmetrical groove (1200). For example, each of the plurality of trenches may have a bottom portion (151a) having a first width (w1) and a side portion (151b) that is in contact with the bottom portion (151a) and has a second width (w2) greater than the first width. By means of this asymmetrical groove (1200), the end portion (157a) of the passivation may be easily positioned in the plurality of trenches, i.e., the first trench (1110).

As will be explained later (see FIGS. 23 to 27), even if the passivation layer (157) is formed on the side surface of the light-emitting portion (151, 152, 153) by the asymmetrical groove (1200) of the first trench (1110), the passivation layer (157) positioned above the first trench (1110) and the passivation layer (157) positioned below the first trench (1110), i.e., the passivation layer (157 of FIG. 23) formed on the photosensitive film, may be spaced apart from each other. In this case, the passivation layer (157) positioned under the first trench (1110) is removed, so that only the passivation layer (157) positioned over the first trench (1110) can be placed on the side of the light-emitting portion (151, 152, 153).

Meanwhile, the angle (θ) between the bottom portion (151a) and the side portion (151b) may be an acute angle, but is not limited thereto. The acute angle (θ) between the bottom portion (151a) and the side portion (151b) means that the depth of each of the plurality of trenches becomes deeper. As the depth of each of the plurality of trenches becomes deeper, as illustrated in FIGS. 23 and 24, the passivation layer (157) positioned above the first trench (1110) and the passivation layer (157) positioned below the first trench (1110) are more easily separated with respect to the first trench (1110), so that the removal of the passivation layer (157) positioned below the first trench (1110) can be facilitated.

Meanwhile, the plurality of trenches are formed so that the passivation layer (157) is preferably not formed on the side of the first conductive semiconductor layer (151), thereby allowing the first electrode (154) to be easily formed on the side of the first conductive semiconductor layer (151). Accordingly, the plurality of trenches can be arranged on the side of the first conductive semiconductor layer (151).

For example, the plurality of trenches may include a first trench (1110) disposed on a first region of a side surface of the first conductive semiconductor layer (151). For example, the plurality of trenches may include at least one second trench (1120) disposed on a second region of a side surface of the first conductive semiconductor layer (151). The second region may be positioned above the first region. For example, the plurality of trenches may include at least one third trench (1130) disposed on a third region of the side surface of the first conductive semiconductor layer (151). The third region may be positioned below the first region.

For example, an end (157a) of the passivation layer (157) may be positioned in the first trench (1110). For example, an end (154a) of the first electrode (154) may be in contact with an end (157a) of the passivation layer (157) in the first trench (1110).

For example, the passivation layer (157) may be disposed in at least one second trench (1120). By disposing the passivation layer (157) in the asymmetric groove (1200) of the second trench (1120), the contact area between the passivation layer (157) and the side of the first conductive semiconductor layer (151) increases, thereby preventing the passivation layer (157) from being detached.

For example, the first electrode (154) may be placed in at least one third trench (1130). By placing the first electrode (154) in the asymmetrical groove (1200) of the third trench (1130), the contact area between the second electrode (155) and the side of the first conductive semiconductor layer (151) increases, thereby strengthening the bonding force of the first electrode (154) and preventing detachment of the first electrode (154).

Meanwhile, as illustrated in Fig. 13, since light generated in the active layer (152) is reflected or scattered by multiple trenches so that more light is extracted, the light extraction efficiency is improved, so that the brightness can be improved.

Meanwhile, referring again to FIGS. 11 and 12, the connecting electrode (350) may be in contact with the first electrode (154) of the semiconductor light-emitting device (150). That is, the connecting electrode (350) may be in contact with the first electrode (154) to be disposed on the side of the semiconductor light-emitting device (150). For example, the connecting electrode (350) may be disposed on the side of the first conductive type semiconductor light-emitting device (150) of the semiconductor light-emitting device (150). In addition, the connecting electrode (350) may be connected to at least one of the first assembly wiring (321) and the second assembly wiring (322). Accordingly, the connecting electrode may connect the first electrode (154) of the semiconductor light-emitting device (150) to at least one of the first assembly wiring (321) and the second assembly wiring (322).

The connecting electrode (350) is in contact with the passivation layer (157) of the semiconductor light emitting element (150) and the inner side of the assembly hole (345) within the assembly hole (345), thereby strengthening the adhesive strength of the connecting electrode (350) and preventing detachment of the connecting electrode (350).

Since the thickness of the passivation layer (157) is relatively thin, the upper side of the connection electrode (350) may be positioned at least lower than the active layer (152) and placed on the side of the first conductive semiconductor layer (151) so that an electrical short does not occur between the connection electrode (350) and the active layer (152) through the passivation layer (157).

For example, the upper side of the connecting electrode (350) arranged on the inner side of the assembly hole (345) and the upper side of the connecting electrode (350) arranged on the side of the semiconductor light emitting element (150) may be at the same position (or height), but this is not limited thereto.

Meanwhile, the electrode wiring (372) may be connected to the second electrode (155) of the semiconductor light-emitting element (150). At least one of the first assembly wiring (321) and the second assembly wiring (322) may be named as the first electrode (154) wiring, and the electrode wiring (372) may be named as the second electrode (155) wiring. In this case, current may flow to the semiconductor light-emitting element (150) by at least one of the first assembly wiring (321) and the second assembly wiring (322) and the assembly wiring (372), and light having a brightness corresponding to the current may be emitted from the semiconductor light-emitting element (150).

The display device (300) according to the first embodiment may include a second insulating layer (360).

The second insulating layer (360) may be formed of an organic material or an inorganic material. For example, the second insulating layer (360) may be disposed on the semiconductor light emitting element (150) and the partition wall (340). The second insulating layer (360) may be disposed in the assembly hole (345). For example, the second insulating layer (360) may be disposed in a groove formed by the connecting electrode (350) within the assembly hole (345).

For example, a part of the second insulating layer (360) may be removed to form a contact hole through which the second electrode (155) of the semiconductor light-emitting element (150) is exposed. Through this contact hole, the electrode wiring (372) may be electrically connected to the second electrode (155) of the semiconductor light-emitting element (150).

Meanwhile, the unexplained symbol 333 is an adhesive layer that can enable the semiconductor light-emitting element (150) to be attached to the first insulating layer (330) within the assembly hole (345).

Hereinafter, a manufacturing process of a semiconductor light-emitting device (150) according to the first embodiment will be described with reference to FIGS. 16 to 29.

Figures 16 to 29 illustrate a manufacturing process of a semiconductor light-emitting device according to the first embodiment.

As illustrated in Fig. 16, a first conductive semiconductor layer (151), an active layer (152), and a second conductive semiconductor layer (153) can be grown on a wafer (401) using deposition equipment such as MOCVD.

As illustrated in FIG. 17, a second electrode (155) can be formed on a second conductive semiconductor layer (153) using a deposition process. In the drawing, the second electrode (155) is formed only in a portion of the upper surface of the second conductive semiconductor layer (153), but this is not limited thereto.

As illustrated in Fig. 18, a mask layer (410) may be formed on the upper electrode. The mask layer (410) may be made of, for example, silicon dioxide (SiO2), but is not limited thereto.

As illustrated in FIG. 19, a first etching process is performed using the mask layer (410) as a mask, so that the second conductive semiconductor layer (153) and the active layer (152) are removed along the vertical direction, and then the first etching process can be stopped after the first conductive semiconductor is removed from the upper surface to a first depth (d1). In this case, a second trench (1120) can be formed in an area where the upper surface and the side of the first conductive semiconductor layer (151) removed to the first depth (d1) meet.

As illustrated in Fig. 20, a secondary etching process may be performed using the mask layer (410) as a mask, and after the first conductive semiconductor layer (151) is removed from the upper surface to a second depth (d2), the secondary etching process may be stopped. In this case, a first trench (1110) may be formed in an area where the upper surface and the side of the first conductive semiconductor layer (151) removed to the second depth (d2) meet.

As illustrated in Fig. 21, a third etching process may be performed using the mask layer (410) as a mask, and after the first conductive semiconductor layer (151) is removed from the upper surface to a third depth (d3), the third etching process may be stopped. In this case, a third trench (1130) may be formed in an area where the upper surface and the side of the first conductive semiconductor layer (151) removed to the third depth (d3) meet.

Thereafter, a fourth etching process is performed using the mask layer (410) as a mask, so that the first conductive semiconductor layer (151) can be removed so that the upper surface of the wafer is exposed.

As illustrated in FIG. 22, a photosensitive film (430) may be formed on the exposed wafer. The upper surface of the photosensitive film (430) may be positioned in the first trench (1110). The photosensitive film may prevent a passivation layer (157) to be described later from being formed on the side of the first conductive semiconductor layer (151) positioned under the first trench (1110).

As illustrated in FIG. 23, a passivation layer (157) may be formed over the entire area of the substrate (310). For example, the passivation layer (157) may be formed on a photosensitive film. For example, the passivation layer (157) may be formed on the mask layer (410). For example, the passivation layer (157) may be formed on a side of the mask layer (410), a side of the second conductive semiconductor layer (153), and a side of the active layer (152). For example, the passivation layer (157) may be formed on a side of the first conductive semiconductor layer (151) positioned over the first trench (1110).

Meanwhile, since the first trench (1110) has an asymmetrical groove (1200), the passivation layer (157) may not be formed in the first trench (1110). That is, the passivation layer (157) formed on the side of the first conductive semiconductor layer (151) positioned above the first trench (1110) with respect to the first trench (1110) and the passivation layer (157) formed on the photosensitive film may be spaced apart from each other. This may be due to a growth difference of the passivation layer (157). For example, the growth of the passivation layer (157) on the side of the first conductive semiconductor layer (151) and the upper surface of the photosensitive film is different, respectively. Due to this growth difference, the passivation layer (157) formed on the side of the first conductive semiconductor layer (151) positioned over the first trench (1110) and the passivation layer (157) formed on the photosensitive film may be spaced apart from each other.

As illustrated in FIG. 24, by removing the surface of the passivation layer (157) using a wet etching process, the passivation layer (157) formed on the side of the first conductive semiconductor layer (151) positioned over the first trench (1110) and the passivation layer (157) formed on the photosensitive film can be spaced further apart, thereby forming a larger gap.

If the distance between the passivation layer (157) formed on the side of the first conductive semiconductor layer (151) positioned over the first trench (1110) and the passivation layer (157) formed on the photosensitive film is sufficient, the wet etching process can be omitted.

As illustrated in FIG. 25, an additional wet process may be performed to remove the passivation layer (157) on the second electrode (155) so that an opening (158) may be formed on the second electrode (155).

As illustrated in FIG. 26, the wafer can be flipped over and transferred onto a transfer substrate (500). That is, the wafer is flipped over so that the second electrode (155) faces the transfer substrate (500), and then the wafer is pressed so that a portion of the semiconductor light-emitting element (150) can be embedded in the adhesive layer (510). In other words, the semiconductor light-emitting element (150) can be attached to the transfer substrate (500) via the adhesive layer (510).

Next, the wafer can be separated by performing the LLO (Lase Lift-Off) process using a laser.

Therefore, as illustrated in Fig. 27, the passivation layer (157) on the photosensitive film can be removed by performing the PLO (PR Lift-Off) process to separate the photosensitive film. The PLO process can be performed using an etchant capable of etching the photosensitive film. In this case, the lower surface (before the semiconductor light-emitting element (150) is turned over) and a portion of the side surface of the first conductive semiconductor layer (151) based on the first trench (1110) can be exposed to the outside.

As illustrated in Fig. 28, after the first electrode (154) is formed, a patterning process may be performed so that the first electrode (154) may be formed on the lower surface and a portion of the side of the first conductive semiconductor layer (151).

As illustrated in FIG. 29, the semiconductor light-emitting element (150) can be manufactured by removing the adhesive layer and separating the transfer substrate (500). For example, the adhesive layer can be removed by the etching solution by immersing the transfer substrate (500) illustrated in FIG. 28 in a container containing an etching solution. By removing the adhesive layer, the transfer substrate (500) can be separated from the semiconductor light-emitting element (150). Thereafter, the semiconductor light-emitting element (150) contained in the container can be recovered using a recovery process.

Although not shown, a cleaning process may be performed to remove residues due to the etchant attached to the recovered semiconductor light emitting element (150).

[Example 2]

Fig. 30 is a cross-sectional view illustrating a semiconductor light-emitting device according to the second embodiment.

The second embodiment is identical to the first embodiment except for the arrangement position of the first electrode (154). In the second embodiment, components having the same shape, structure, and/or function as those in the first embodiment are given the same drawing reference numerals and detailed descriptions are omitted.

Referring to FIG. 30, a semiconductor light-emitting device (150A) according to the second embodiment may include a light-emitting portion (151, 152, 153), a first electrode (154), a second electrode (155), trenches (1110, 1120, 1130), and a passivation layer (157). The semiconductor light-emitting device (150A) according to the second embodiment may include more components than this.

The light-emitting portion may include a first conductive semiconductor layer (151), an active layer (152), and a second conductive semiconductor layer (153).

A plurality of trenches may be arranged on the side of the light-emitting portion. For example, a plurality of trenches may be arranged on the side of the first conductive semiconductor layer (151).

The plurality of trenches may include a first trench (1110), at least one second trench (1120) positioned above the first trench (1110), and at least one third trench (1130) positioned below the first trench (1110).

For example, the passivation layer (157) may be disposed on the upper portion of the second electrode (155) and on the side of the light-emitting portion. For example, the passivation layer (157) may be disposed in the second trench (1120). For example, the end (157a) of the passivation layer (157) may be located in the first trench (1110).

For example, the first electrode (154) may be placed on the lower and side portions of the first conductive semiconductor layer (151).

For example, the first electrode (154) may be disposed in the third trench (1130). For example, the first electrode (154) may be disposed in the first trench (1110). For example, the first electrode (154) may be disposed on the passivation layer (157). In other words, the first electrode (154) may extend from the lower portion of the first conductive semiconductor layer (151) to the passivation layer (157) via the third trench (1130) and the first trench (1110) disposed on the side of the first conductive semiconductor layer (151).

Accordingly, by disposing the first electrode (154) over a wider area on the side of the light-emitting portion, the contact area between the connecting electrode (350) and the semiconductor light-emitting element (150A) is maximized, so that maximum brightness can be obtained.

In addition, since the first electrode (154) is disposed not only on the first conductive semiconductor layer (151) but also on the passivation layer (157), the bonding strength of the first electrode (154) can be strengthened and detachment of the first electrode (154) can be prevented.

The above detailed description should not be construed as restrictive in all respects but should be considered as illustrative. The scope of the embodiments should be determined by a reasonable interpretation of the appended claims, and all changes within the equivalency range of the embodiments are intended to be included within the scope of the embodiments.

The embodiment can be adopted in the field of displays that display images or information.

The embodiment can be adopted in the field of displays that display images or information using semiconductor light-emitting elements. The semiconductor light-emitting elements can be micro-level semiconductor light-emitting elements or nano-level semiconductor light-emitting elements.

Claims (20)

luminescent part;
A first electrode on the lower and side portions of the above light-emitting portion;
A second electrode on the upper part of the above light emitting portion;
a plurality of trenches on the side of the above light-emitting portion; and
A passivation layer is included on the side of the above light-emitting portion,
The end of the passivation layer is positioned in one of the plurality of trenches,
A semiconductor light emitting device, wherein an end of the first electrode is in contact with an end of the passivation layer in the one trench. In the first paragraph,
The above plurality of trenches are arranged along the perimeter of the side of the above light-emitting portion.
Semiconductor light emitting device. delete delete In the first paragraph,
The tip of the first electrode is positioned on the passivation layer.
Semiconductor light emitting device. In the first paragraph,
Each of the above plurality of trenches has an asymmetrical groove.
Semiconductor light emitting device. In Article 6,
Each of the above plurality of trenches has a bottom portion having a first width and a side portion contacting the bottom portion and having a second width greater than the first width.
Semiconductor light emitting device. In Article 7,
The angle between the above bottom and the above side is an acute angle.
Semiconductor light emitting device. In the first paragraph,
The above light emitting part,
First challenge type semiconductor layer;
An active layer on the first challenge type semiconductor layer; and
A second conductive semiconductor layer is included on the above active layer,
The above plurality of trenches are arranged on the side of the first challenge type semiconductor layer.
Semiconductor light emitting device. In Article 9,
The above multiple trenches are,
A first trench on the first region of the side of the first challenge type semiconductor layer; and
At least one second trench is included on the second region of the side of the first challenge type semiconductor layer.
Semiconductor light emitting device. In Article 10,
The end of the above passivation layer is located in the first trench.
Semiconductor light emitting device. In Article 11,
The end of the first electrode is in contact with the end of the passivation in the first trench.
Semiconductor light emitting device. In Article 10,
The above passivation layer is disposed in at least one second trench.
Semiconductor light emitting device. In Article 10,
The above multiple trenches are,
At least one third trench is included on the third region of the side of the first challenge type semiconductor layer,
The above first electrode is placed in at least one third trench.
Semiconductor light emitting device. In the first paragraph,
The above first electrode includes a reflective layer.
Semiconductor light emitting device. substrate;
First and second assembly wirings on the above substrate;
A bulkhead disposed on the first and second assembly wiring and having an assembly hole;
A semiconductor light emitting element in the above assembly hole; and
A connecting electrode is disposed in the assembly hole and connects the semiconductor light emitting element to at least one of the first and second assembly wirings,
The above semiconductor light emitting device,
luminescent part;
A first electrode on the lower and side portions of the above light-emitting portion;
A second electrode on the upper part of the above light emitting portion;
a plurality of trenches on the side of the above light-emitting portion; and
A passivation layer is included on the side of the above light-emitting portion,
The end of the passivation layer is positioned in one of the plurality of trenches,
A display device, wherein the above connecting electrode is arranged along the periphery of the semiconductor light-emitting element within the above assembly hole. In Article 16,
The above connecting electrode is in contact with the first electrode of the semiconductor light emitting element.
Display device. In Article 17,
The above connecting electrode is in contact with the passivation layer of the semiconductor light emitting element and the inner surface of the assembly hole within the assembly hole.
Display device. delete In Article 16,
an insulating layer on the above bulkhead; and
Including electrode wiring connected to the semiconductor light emitting element through the insulating layer.
Display device.

Images